The invention relates to a pipe coupling for two pipe ends, which have an annular flange situated on each pipe end. Such a device may consist of at least two part shells flexibly interconnected, for example, by means of a connecting bolt and of a clamping lever lock, with engagement means, such as flanges, situated on the part shells and extending inwards radially, which engage behind the annular flanges when the device is closed, and with an intermediate member connecting the pipe end, which is sealed off with respect to each pipe end by means of an annular seal.
In a pipe coupling of this kind, the two pipe ends which are to be coupled are of identical structural form, which is advantageous as compared to other types of pipe couplings wherein one pipe end is constructed as a plug-in part and one pipe end as a socket part.
In a pipe coupling of the kind defined in the foregoing, the two pipe ends are constructed as socket parts in each case, that is to say of identical shape, whereas an intermediate member is ambilaterally constructed as a plug-in part, so that the pipe ends may be pushed on to the intermediate member. An annular seal is inset in each case in the internal surface of the pipe ends, whereby the seal required between the socket part and plug-in part is obtained.
To this end, the pipe ends have attachment members, which are initially machined as separate structural components, meaning that the annular flanges, the bearing surfaces for the flanges of the part shells and the internal circumferential grooves for the insertion of the annular seals, are produced by appropriate machining operations. It is only after completion of this production sequence that these pipe ends are interwelded with the actual pipe member. For this purpose, the end face of the pipe member and the end face of the pipe end which is to be attached must be cut very precisely and machined with care, because the welding seam which is to be formed between these end faces should not only have an adequate mechanical load-carrying capacity but should also be completely fluid etc. tight, so that a liquid or gaseous fluid cannot escape from the pipe duct.
The known form of embodiment has numerous disadvantages, whereof one consists in that the interwelding between the pipe ends of the corresponding pipe sections is relatively costly because of the great care required, and in that the welding seam nevertheless remains a source of risk within the pipe interior. It is disadvantageous moreover that difficulties frequently arise in the coating of the pipe ends with a protective layer, for example, during pot galvanizing, since this should in any event be performed prior to complete finishing of the pipe end, to avoid damaging the annular seal. A pot galvanizing operation is frequently also disadvantageous however, in the area of the annular groove receiving the joint, so that further difficulties are engendered by possible covering of the groove. Another disadvantage in this connection consists in that a protective layer of this kind is interrupted in the area of the welding seam, when the pipe end is being welded on.